Quick Glock 23/9mm conversion Q for USPSA use.

Quick, simple question....
I need to know soon if it would be "legal" in USPSA (Production) for me to use a Glock 23 model pistol with a 9mm conversion barrel installed? I like the idea of having a G23 (which is .40) that would be able to switch over to 9mm for competition (because it's more affordable for me). Originally I was just going to just get a G19, but the idea of the interchangeable barrel system popped into my head, and I have an opportunity to get a G19 for cheap... but before I go out and buy I need to know... I actually shoot a 1911 in Limited 10 now, but I want to play around in the Production side of things.

Also, how do the mags work when changing out calibers in Glocks? Will the Mags for the G23 still work with 9mm bullets in them, or do you have to buy others? If so, which one?

thanks

Thank you. And yes, I do have a rule book, I just don't know where it is at the moment.

So I'll probably end up getting a G19. I'm guessing then, that I can't convert over a G19 (9mm) to any other caliber by changing out the barrel, right? I don't know, but it seems by common sense that I couldn't go from smaller to larger cal. (I do know I could go even smaller and get a .22 conversion kit - obviously, but I'm not really interested in that).

Well, since everything is scored minor in Production anyway I guess it wouldn't really be an advantage, and in the long run, would just cost me more in ammo. And since I already shoot in Limited 10, I'll stick with my 1911 for that.

I would never try to sneak by doing something wrong. I was just asking about converting the 9mm to higher cal. because ideally, I'd like to have a gun that is able to be multi functioning.

With my second Question, I was just hoping I could have a G19 and be able to also convert it UP to a .40 if I wanted to for a self protection, although I knew it unlikely.

Since I didn't know the rules on switching out barrels in USPSA, I was hoping that I could just buy a .40 for self protection AND also have it double as my Production competition gun so therefore be able to switch it to a 9mm barrel.

No need to shoot higher than 9mm in Production anyway since everything is scored Minor anyway.